In manufacturing semiconductor devices such as LSI and super-LSI or in manufacturing a liquid crystal display board or the like, a pattern transferring is conducted by irradiating light to an exposure original plate such as a semiconductor wafer or an original plate for liquid crystal, but if a dust particle exists adhering to the exposure original plate, the dust particle absorbs the light or refracts it, giving rise to deformation and roughened edges to a transferred pattern and black stains to a white background, which lead to problems such as a damaged dimension, a poor quality, a deformed appearance, and lowering of the performance and the yield of the finished device.
Thus, these works are usually performed in a clean room; however, even in a clean room it is difficult to keep the exposure original plate in a dust-free state all the time; for this reason, a pellicle, which transmits the exposure light well, is attached to a surface of the exposure original plate as a dust-fender. Under such circumstances, dust does not directly adhere to the surface of the exposure original plate but only onto the pellicle membrane, and thus, in lithography operation, by setting a photo focus on the pattern formed on the exposure original plate, the dust particles on the pellicle membrane fail to cast their shadows in the image transfer performance.
A basic construction of a pellicle is shown in FIG. 1 and FIG. 2. A transparent pellicle membrane 3, which is made of a material that is highly transmitting to the lights used in light exposure such as cellulose nitrate, cellulose acetate and a fluorine-containing resin, is adhered to one of the two annular faces of a pellicle frame 1 (hereinafter referred to as “upper annular face”), made of an aluminum alloy such as A7075, A6061 and A5052 to which a black alumite processing has been applied, or of a pellicle frame 1 made of stainless or polyethylene or the like, or of a pellicle frame 1 of aluminum or other metal which is coated with a substance—the adhering of the transparent pellicle membrane 3 is effected by laying a solvent capable of dissolving the pellicle membrane on the upper annular face and drying the solvent by air flow (ref. IP Publication 1), or by laying an adhesive 2 such as acrylic resin, epoxy resin and fluorine-containing resin (ref. IP Publications 2 and 3); and furthermore, on the other one of the two annular faces of the pellicle frame 1 (hereinafter referred to as “lower annular face”) is laid an agglutinant layer 4 made of a polybutene resin, a polyvinyl acetate resin, an acrylic resin, a silicone resin or the like; and over this agglutinant layer 4 to adhere to a photomask is laid a releasable liner 5 for protecting the agglutinant layer.